Roving frame bolster

ABSTRACT

A vibration free mounting arrangement for a spindle assembly in a roving frame wherein the spindle shaft is softly suspended to produce a natural frequency of vibration substantially below the frequency of vibration inducing forces on the spindle assembly when the assembly is operating at relatively high speed. The mounting arrangement, preferably, includes a resiliently mounted bolster tube for pivotally supporting the spindle assembly and a stabilizer assembly which dampens residual oscillatory motion of the spindle assembly.

United States Patent [191 Kieronski Feb. 5, 1974 ROVING FRAME BOLSTER 2,650,465 9/1953 51/135 [75] Inventor: John P. Kieronski, Charlotte, NC. 369L747 9/1972 llanova 5 I135 Assignee: Whitin Machine Works, Inc.,

Primary Examiner-John Petrakes Assistant Examiner-Charles Gorenstein Attorney, Agent, or Firm-McNenny, Farrington, Pearne & Gordon Charlotte, NC.

[22] Filed: Oct. 26, 1971 ABSTRACT A vibration free mounting arrangement for a spindle Appl. No.: 192,074

52 US. 57 71, 57 102, 57 135, l 1 l 3080139 assembly in a roving frame wherein the spindle shaft 15 Dolh 7/12, Dolh 7/42 softly suspended to produce a natural frequency of vi- 57/102, 134,135, 136, 71;

[51] Int. [58] Field of Search bration substantially below the frequency of vibration inducing forces on the spindle assembly when the assembly is operating at relatively high speed. The mounting arrangement, preferably, includes a resil- [56] References Cited UNITED STATES PATENTS iently mounted bolster tube for pivotally supporting the spindle assembly and a stabilizer assembly which s a 6 .l d n .1 D. S e h s n m 0 g n N O g o .m m m V. r r. D m a 4 n 9 m m S 0 m l M C u d 8 sq 1 e r m 1 m b m 8 dm %XXX 70mm mm M W mun a "H e t r 0 .mp nSm aoa MHYC 5274 7935 8899 llll 2557 2 36 01 i 6503 R788 22 til. m

.ROVING FRAME BOLSTER BACKGROUND OF THE INVENTION The invention relates to improvements in roving frame spindle assemblies and, more particularly pertains to a spindle assembly mounting arrangement for vibrationless high speed operation.

FIELD OF THE INVENTION Roving frames used in the processing of various yarns are generally provided with a plurality of identical stations at each of which a strand is drafted and twisted by a rotating device or flyer and wound onto a bobbin.

The flyer is normally mounted on a revolving spindle shaft as an assembly. An important factor limiting the production rate of a typical roving machine has been .the rotational speed capacity of its spindle assembly.

Even though it has been a common practice to precision balance the flyers and associated spindle shafts, excessive spindle assembly vibration has occurred during operation at relatively high speed. Such vibration may lead to fatigue and eventual failure of various parts resulting in increased costs which are not offset by the higher speed. The source of this vibration, in some instances, has been the result of a resonant condition in the spindle assembly where a driving force on the assembly is approximately equal to a natural vibration frequency of the assembly.

In one prior typeof machine, the spindle assemby includes a relatively long spindle shaft carrying the flyer at the upper end. The shaft is journaled in axially spaced radial bearings from its other end-The bearing nearest the flyer is mounted in a rigid bolster tube arranged to reciprocate along the axis of the spindle shaft relative to the main frame while the other bearing is fixed to the main frame. This arrangement requires that the unsupported length of the spindle shaft, when the bolster is in its lowermost position, be at least as great as the reciprocation stroke of the bolster. Because of limited shaft support, physical space, and associated geometries the stiffness of these members is somewhat limited. Consequently, at a resonant vibration condition, the amplitude of vibration may become unacceptable. Unfortunately, it is found that this resonance tends to occur at speeds about equal to or slightly higher than the upper limits of conventional operating speeds. Production rates have thus been restricted by the necessity of operating below the critical resonant speed.

SUMMARY OF THE INVENTION According to the present invention, resilient mounting means is provided for the individual spindle assemblies of a roving frame which substantially eliminates objectionable spindle assembly vibration at moderate to high spindle speeds. The deflection rate or stiffness of the mounting means is selected to make the natural or resonant vibration frequency of the spindle assembly substantially lower than the frequency rate of variable forces operatingon the spindle assembly when the assembly is driven at commercially advantageous speeds.

In the preferred embodiment, the resilient mounting means includes an elastic bushing radially gripping a base end of a bolster tube. Deformation of the bushing permits the upper free end of the bolster tube to'pivot or rock laterally. A spindle shaft, radially fixed in a bearing at one end, extends upward through the bolster tube where it is journaled in a radial bearing in the free end of the bolster tube. The elastomeric bushing supports the spindle shaft by resisting deflection of the bolster tube. According to this preferred arrangement, the length of the bolster tube operates as a lever on the bushing to reduce its deflection or spring rate and to provide a more linear and predictable deflection rate for small displacements of the spindle shaft.

According to the invention, in greater detail, means are provided to adjustably prestress the elastic bushing of the mounting means to achieve an optimum stiffness rate. As disclosed, the adjusting means comprises an adjustable nut disposed at one end of the elastomeric bushing for compressing the bushing in a bolster bracket.

According to a further aspect of the invention, a stabilizer unit is provided to improve the stability of the spindle assembly by damping weaving or secondary oscillation of the spindle assembly resulting from the relative softness of the mounting means. The stabilizer unit includes a friction pad girdling the spindle shaft and damping its oscillation by frictional engagement with surfaces fixed to the frame of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevational view, partially in cross section, of a roving frame spindle station constructed in accordance with the invention.

FIG. 2 is a perspective view of a bolster, on a somewhat enlarged scale, with the upper portion of the bolster broken away.

FIG. 3 is an elevational cross-sectional view of the bolster assembly illustrated in FIG. 2.

FIG. 4 is an enlarged view of a portion of the bolster assembly illustrating details of the resilient mounting arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and in particular to FIG. I, there is shown a typical spindle station ll) of a roving frame. A bolster bracket ll vertically supports a bolster tube 12 in a manner fully detailed hereinbelow. The bolster tube 12, in turn, supports a bobbin 13 and spindle shaft 14. A strand guide and twisting device or flyer 16 is mounted on the upper end of the spindle shaft 14. A roving frame or machine, typically, includes a plurality of spindle stations 10 regularly arranged into a row or rows. While, for conciseness, the present description discusses only one such spindle station 10 it is to be understood of course, that the principles of the invention will normally be applied to all of the spindle stations of a particular machine.

The bolster bracket 11 is rigidly affixed to a frame rail 17. The frame or bolster rail 17 in the type of machine under consideration here may be common to all of the spindle stations of the machine. The bolster rail 17 is mounted on a carriage frame (not shown) which is controlled by a builder motion to provide vertical reciprocation of the rail 17 relative to a stationary frame member 15 of the roving frame. As best illustrated in FIGS. 3 and 4, the bolster bracket ll has a cylindrical bore 19 extending vertically through its unsupported or outward end. At its lower end, the cylindrical bore 19 terminates in a bottom surface or shoulder .21 extending radially inward to a smaller cylindrical bore 22 so that the major cylindrical bore 19 forms a counter-bore with this minor bore 22.

The bolster tube 12 is mounted or held in the bolster bracket 11 by resilient means in the form of an elastomeric bushing 31 positioned in the bore 19. The bolster tube 12 is desirably in the shape of an elongated cylindrical tube of generally uniform wall thickness. At its lower end, the bolster tube 12 has an annular recess or groove 26 machined in its exterior. Adjacent its upper end, the bolster tube 12 is provided with an internal radial shoulder 27. A sleeve bearing 28 is press fitted into the upper end of the bolster tube 12 and is abutted against the radial shoulder 27.

The upper side of the bolster bracket 11 is machined to form a face 33 perpendicular to the major bore 19. A thrust washer 34, positioned on this face 33, axially supports a bobbin gear 36 thereon. The bobbin gear 36 is journaled on the exterior of the bolster tube 12 by means of sleeve bearing 37 retained in the bobbin gear by a press fit. The bobbin gear 36 is rotatably driven by a larger gear 38 which, in turn, is driven by a power source (not shown) of the roving frame. The larger drive gear 38 is vertically reciprocated with the bolster rail 17. The bobbin 13 is axially supported on the bobbin gear 36 and is radially supported or journaled on the exterior of the bolster tube 12. A pin 39 fixed to the bobbin gear 36 is received in a radial slot 41 at the base of the bobbin 13 and transmits rotary motion of the gear 36 to the bobbin 13.

The spindle shaft 14 is an elongated cylindrical member mounted for rotation about a generally vertical axis in a bearing or bushing 46 at its lower end and the bolster sleeve bearing 28. The lower or footstep bearing 46 includes a lower end wall 47 which axially supports the shaft 14 while the remaining upper portion of the bearing 46 radially supports the shaft. This bearing 46 is fixed in a bore 48 provided in a step bracket 49. The step bracket 49 is rigidly fixed to the frame member through a step rail 51 which is common to the step brackets associated with the other spindle stations of the machine.

The spindle shaft 14 includes a stem portion 53 of reduced diameter at its upper end. The flyer 16 includes a depending hub projection 57 having an internal bore 58 closely fitting the diameter of the spindle stem 53. A diametral slot 59 is provided in the upper end of the stem 53 for cooperation with a cross pin 61 through the flyer hub 57 to transmit rotation of the spindle shaft 14 to the flyer 16 and permit the flyer to be manually removed from the shaft. The spindle shaft 14 is driven by a power source (not shown) which rotates a drive gear 71 meshing with a spindle gear 72 fixed to the spindle shaft 14.

In operation a roving strand drawn from sliver in the drafting section (not shown) passes through a radial hole 66 in an upper end 67 of the hub 57 down through a tubular leg 68 of the flyer 16 and through an eye 69 of a presser paddle 70. The roving strand is wound on the bobbin 13 as the bobbin is caused to rotate by the bobbin gear 36. The strand is simultaneously twisted by rotation of the spindle shaft 14 and flyer 16 in a manner well known to those skilled in the art. During such operation the bolster rail 17 cyclically reciprocates up and down to cause a strand to be wound on the full length of the bobbin 13. Thus, the distance between the bearings 28 and 46 radially supporting the spindle assembly varies. FIG. 1 illustrates the lower position of the bolster tube 12 where the greatest portion of the spindle shaft 14, above the bolster tube, is cantilevered.

As illustrated in FIGS. 3 and 4, the bolster tube 12 is resiliently held or mounted in the bolster bracket 11 by the elastomeric bushing 31. The bushing 31 may be formed of any suitable resiliently deformable material such as rubber or other elastomer. According to the preferred embodiment of the invention the bushing is made of Buna N rubber of about Durometer hardness. The bushing 31 is, preferably, provided in the form of a cylindrical sleeve having an outer peripheral groove or relief 71. In a free state, the inside diameter of the bushing 31 is approximately equal to the diameter of the peripheral groove 26 on the bolster tube 12. Similarly, the free outer diameter of the bushing 31 is approximately equal to the diameter of the major bore 19 of the bolster bracket 11.

The tube 12 is assembled with the bolster bracket 11 by first slipping the bushing 31 onto the peripheral groove 26 of the tube 12 and then lowering the tube and bushing into the bore 19 until a lower end face 72 of the bushing abuts the radial face 21 at the base of the bore 19. An externally threaded nut 74 is slipped over the bolster tube 12 and threaded into a threaded upper portion of the bore 19. As shown in FIG. 4, the nut 74 is provided with at least one axial hole 76 for wrenching the nut against the elastic bushing 31.

The nut 74 may be adjusted against the bushing 31 until axial compression of the bushing 31 is sufficient to adequately grip and support the bolster tube 12 and a desired deflection rate of the bushing is obtained. The tightened condition of the bushing 31 is illustrated in FIG. 4. The bushing 31 may be slightly distorted in compression so that the bushing is pulled slightly away from the bolster tube groove 26 at its axial ends while the center portion at the peripheral groove 71 is forced radially inward to more tightly grip the bolster tube 12. The vertical load of bolster tube 12 is supported by the bushing 31 at an upper radial face 77 of the groove 26.

Vibration of the spindle shaft 14 and flyer 16 is transmitted through the sleeve bearing 28 and causes the bolster tube 12 to rock or deflect laterally. Ideally, the bolster tube 12 rocks or pivots about an imaginary point at or about the geometric center of the bushing 31. Desirably, the minor cylindrical bore 22 in the bolster bracket 11 and a cylindrical bore 81 in the nut 74 are of the same diameter which is chosen with regard to the outer diameter of the bolster tube 12 to limit lateral deflection of the bolster tube 12. For instance, with the extreme lower left portion of the bolster tube abutting the adjacent portion of the bore 22 and a portion of the bolster tube above the bushing 31 abutting the adjacent righthand portion of the nut 74, the upper end of the tube and the bearing 28 may move approximately one-fourth of an inch laterally from a vertical axis defined by the major bore 19 of the bolster bracket 11.

It will be understood that the bolster tube 12 operates on the elastomeric bushing 31 as a lever in transmitting vibrational forces on the sleeve bearing 28 from the spindle shaft 14 at the upper or free end of the bolster tube 12. This arrangement reduces the effective stiffness of the bushing 31 and minimizes the amount of deformation required in the bushing for a relatively large deflection of the upper free end of the bolster tube 12 so that the deflection rate or spring rate produced with the bushing 31 and transmitted to the sleeve bearing 28 is relatively low. It may also be understood that, owing to the proximity of the bobbin gear 36 to the imaginary pivot point at the geometrical center of the bushing 31, the bobbin gear 36 remains in alignment with the drive gear 38 since relatively large lateral deflections of the upper end of the bolster tube 12 produce only slight displacements of the tube adjacent the bolster bracket 1 1.

Lateral displacement of the bolster tube 12 allows the spindle shaft 14 and flyer 16 to pivot as an assembly laterally about the lower end of the shaft on the end wall 47 of the footstep bearing 46. The inside diameter of the bolster tube 12 provides a clearance for lateral displacement of the shaft 14 and the bearings 46 and 28 supporting the shaft are provided with a slight clearance to accommodate such lateral movement. As may be appreciated, the relative softness or elasticity of the bushing 31 and the leverage provided by the length of the bolster tube 12 result in an exceptionally soft mounting or suspension of the spindle tube 14 and flyer 16. In operation, the spindle assembly exhibits a behavior closely analogous to the dynamics of a spinning top at normal operating speedsv of between about 900 r.p.m. to 1200 r.p.m., for instance. Due to the softness or low spring rate of the elastic bushing, the spindle assembly may have a tendency to nutate in a motion similar to precession of a spinning top. A stabilizer assembly 86, shown in cross section in FIG. 3, is provided to damp out this nutational or precessing movement.

The stabilizer assembly 86 includes a mounting bracket 87, a friction pad 88, a compression spring 89, a friction washer 91 and a retaining housing 92. The mounting bracket 87 is fixed against the bolster bracket 11 by the bolt 18. The retaining housing 92 is secured to the mounting bracket 8.7.by screws 90 (FIG. 2). The retaining housing 92and compression spring 89 are dimensioned so that the spring is compressed in the housing 92 against the friction washer 91 and friction pad 88. The plane of the friction pad or disk 88 is generally perpendicular to the ideal vertical axis of rotation of the shaft 14. The spindle shaft 14 is assembled through clearance holes or apertures 93, 94 and 95, in the housing 92, washer 91, and bracket 87, respectively, which are sufficiently large to permit limited lateral movement of the spindle shaft 14 therein. A central bore 97 in the friction pad 88 is slightly larger than the diameter of the spindle shaft 14 to provide radial clearance therebetween so that the pad 88 is not rotated by the spindle shaft. Lateral movement of the spindle shaft 14 is, nevertheless, resisted or dampened by the pad 88 by means of engagement between the shaft and the wall of the bore 97. The pad 88is caused to more radially with the shaft 14 to dissipate energy through sliding frictional contact betweenthe surfaces of the bracket 87 and washer 91.

It has been found that force impulses from gear teeth irregularities, spacing errors, misalignment and the like associated withthe spindle drive gears 71 and 72 are transmitted to the spindle shaft 14 and cause the assembly of the spindle shaft 14 andflyer 16 to vibrate. The frequency rate of these forces operating on the spindle shaft are proportional to the speed at which the shaft is driven. The natural frequency at which the spindle shaft 14 and flyer l6 vibrates, generally, depends on the composite stiffness .of the spindle shaft 14 and the bolster structure in which it is journaled in relation to the mass of these members and the mass of other parts such as the bobbin members and the fiber on the bobbin which may vibrate with the spindle shaft 14 and flyer 16.

In various spindle station arrangements which may be contemplated, other sources of vibrational forces on the spindle assembly, besides those created by the spindle drive gears, may be significant or dominant. Potential sources of vibrational forces may include the drive train associated with the bobbin or an unbalance of the spindle assembly. In such cases as these, the vibrational force generally varies either in magnitude or direction with a frequency proportional to the rotational speed of the spindle shaft.

It has previously been customary to provide the bolster bracket 11 and bolster tube 12 as a rigid integral member. This has previously resulted in an arrangement wherein the spindle shaft 14 and flyer l6 assembly vibrates objectionably when the spindle 14 is driven near a certain resonant speed, for instance about.950 r.p.m. At or around this speed the fluctuating forces operating on the spindle shaft in such prior arrangements where amplified through resonance and caused the spindle assembly to vibrate excessively.

According to the invention, it may be appreciated that the resilient mounting of the bolster tube 12 pro duces a relatively soft mounting or suspension of the spindle shaft 14 and thereby greatly reduces the natural or resonant frequency of the spindle assembly from that of previously employed spindle shaft mounting arrangements. By operating the spindle assembly at a speed where the vibration inducing or driving forces on it are substantially higher than the natural frequency, these vibration forces are no longer significantly amplitied and the amplitude of vibration is acceptable. In one working model embodying the invention the resilient mounting of the spindle shaft 14 as described produces a resonant condition at a speed between about 100 and 200 r.p.m. and allows the spindle to be driven with minimal vibration at a desired speed of about 1,200 r.p.m.

The foregoing description is necessarily detailed in character so that the invention may be completely set forth, but it will be understood that modifications may be made in its construction and details without departing from the principles and spirit of the invention.

What is claimed is:

l. A roving frame comprising a spindle assembly for twisting a strand of fibers to be wound on a bobbin, the spindle assembly including a rotatable spindle shaft and a flyer fixed to the shaft, drive means including means for rotating said spindle shaft at a desired speed and means for rotating the bobbin, resilient mounting means on said frame resiliently supporting said spindle shaft relative to the frame, said mounting means including an elongated element axially aligned with said spindle shaft, bearing means fixed to said element and radially supporting said spindle shaft, said resilient mounting means including a resilient member supporting said element at a point axially spaced from said bearing means.

2. A roving frame as set forth in claim 1 wherein said resilient member supports said element for pivotal movement.

3. A roving frame as set forth in claim 2 wherein said element is a tube concentric about said spindle shaft.

4. A roving frame as set forth in claim 3 wherein a tubular bobbin assembly is journaled about said tube element.

5. A roving frame as set forth in claim 4 wherein said bobbin assembly includes a power driven gear journaled on said tube element, said gear being closely adjacent said resilient member.

6. A roving frame as set forth in claim 5 wherein said tubular element is axially reciprocal relative to said spindle shaft.

7. A roving frame as set forth in claim 6 wherein said spindle shaft is radially fixed relative to said frame at an end opposite the end associated with said flyer.

8. A spindle mounting assembly in a roving frame comprising an elongated rotatable spindle shaft, a flyer fixed at one end of the spindle shaft, mounting means for supporting the spindle shaft on the frame, said mounting means including a support member having a radial bearing fixed adjacent to one end thereof and being pivotally mounted relative to the roving frame adjacent its other end, said spindle shaft being journaled in said radial bearing, and resilient means yieldably resisting pivotal movement of said support member and radial displacement of said shaft.

9. A spindle mounting assembly as set forth in claim 8 wherein said resilient means comprises an elastic member which by deformation thereof provides the pivotalmounting of said support member.

10. A spindle mounting assembly as set forth in claim 9 wherein said support member is a circular tube concentric about said shaft and said elastic member is a cylindrical bushing engaging the outer surface of said tube.

11. A spindle mounting assembly as set forth in claim 10 wherein said elastic bushing is precompressed in a rigid mounting bracket.

12. A spindle mounting assembly as set forth in claim 10 wherein said tube is disposed within a rigid bore such that said bore limits pivotal movement of said tube.

13. A spindle mounting assembly as set forth in claim 8 wherein a friction pad, radially movable with said shaft upon vibration thereof, frictionally engages a stationary friction surface to dampen vibration of said shaft.

14. In a spindle station of a roving frame including an elongated spindle shaft, a flyer fixed to one end of the spindle shaft, a first bearing fixed relative to a main frame, a bolster assembly including means to support a bobbin thereon and a bolster tube generally concentric about the axis of rotation of the spindle shaft, 3 second bearing mounted on the bolster assembly in one end of the bolster tube, means to reciprocate the bolster assembly in a direction along the axis of rotation of the spindle shaft, said spindle shaft being radially supported in said bearings with said one end cantilevered, and drive means for rotating the spindle shaft and flyer, the improvement comprising mounting means for resiliently supporting the bolster tube at an end opposite said one end and permitting the tube to pivot at such opposite end, said mounting means including means determining a predetermined deflection rate of the tube whereby lateral vibration of said spindle shaft is resisted by said mounting means through said tube.

15. The combination as set forth in claim 14 wherein said resilient mounting means comprises a circular elastic bushing radially gripping the exterior of said bolster tube and mounted in a bore of a rigid bolster bracket.

16. The combination as set forth in claim 15 wherein said circular bushing is a tubular generally cylindrical bushing having peripheral relief means therein.

17. The combination as set forth in claim 16 wherein adjustment means are provided to adjustably compress said bushing in said bore and thereby adjust the deflection rate of said bushing.

18. The combination set forth in claim 14 including damping means arranged to resist lateral deflection and movement of said spindle shaft with a frictional force. 

1. A roving frame comprising a spindle assembly for twisting a strand of fibers to be wound on a bobbin, the spindle assembly including a rotatable spindle shaft and a flyer fixed to the shaft, drive means including means for rotating said spindle shaft at a desired speed and means for rotating the bobbin, resilient mounting means on said frame resiliently supporting said spindle shaft relative to the frame, said mounting means including an elongated element axially aligned with said spindle shaft, bearing means fixed to said element and radially supporting said spindle shaft, said resilient mounting means including a resilient member supporting said element at a point axially spaced from said bearing means.
 2. A roving frame as set forth in claim 1 wherein said resilient member supports said element for pivotal movement.
 3. A roving frame as set forth in claim 2 wherein said element is a tube concentric about said spindle shaft.
 4. A roving frame as set forth in claim 3 wherein a tubular bobbin assembly is journaled about said tube element.
 5. A roving frame as set forth in claim 4 wherein said bobbin assembly includes a power driven gear journaled on said tube element, said gear being closely adjacent said resilient member.
 6. A roving frame as set forth in claim 5 wherein said tubular element is axially reciprocal relative to said spindle shaft.
 7. A roving frame as set forth in claim 6 wherein said spindle shaft is radially fixed relative to said frame at an end opposite the end associated with said flyer.
 8. A spindle mounting assembly in a roving frame comprising an elongated rotatable spindle shaft, a flyer fixed at one end of the spindle shaft, mounting means for supporting the spindle shaft on the frame, said mounting means including a support member having a radial bearing fixed adjacent to one end thereof and being pivotally mounted relative to the roving frame adjacent its other end, said spindle shaft being journaled in said radial bearing, and resilient means yieldably resisting pivotal movement of said support member and radial displacement of said shaft.
 9. A spindle mounting assembly as set forth in claim 8 wherein said resilient means comprises an elastic member which by deformation thereof provides the pivotal mounting of said support member.
 10. A spindle mounting assembly as set forth in claim 9 wherein said support member is a circular tube concentric about said shaft and said elastic member is a cylindrical bushing engaging the outer surface of said tube.
 11. A spindle mounting assembly as set forth in claim 10 wherein said elastic bushing is precompressed in a rigid mounting bracket.
 12. A spindle mounting assembly as set forth in claim 10 wherein said tube is disposed within a rigid bore such that said bore limits pivotal movement of said tube.
 13. A spindle mounting assembly as set forth in claim 8 wherein a friction pad, radially movable with said shaft upon vibration thereof, frictionally engages a stationary friction surface to dampen vibration of said shaft.
 14. In a spindle station of a roving frame including an elongateD spindle shaft, a flyer fixed to one end of the spindle shaft, a first bearing fixed relative to a main frame, a bolster assembly including means to support a bobbin thereon and a bolster tube generally concentric about the axis of rotation of the spindle shaft, a second bearing mounted on the bolster assembly in one end of the bolster tube, means to reciprocate the bolster assembly in a direction along the axis of rotation of the spindle shaft, said spindle shaft being radially supported in said bearings with said one end cantilevered, and drive means for rotating the spindle shaft and flyer, the improvement comprising mounting means for resiliently supporting the bolster tube at an end opposite said one end and permitting the tube to pivot at such opposite end, said mounting means including means determining a predetermined deflection rate of the tube whereby lateral vibration of said spindle shaft is resisted by said mounting means through said tube.
 15. The combination as set forth in claim 14 wherein said resilient mounting means comprises a circular elastic bushing radially gripping the exterior of said bolster tube and mounted in a bore of a rigid bolster bracket.
 16. The combination as set forth in claim 15 wherein said circular bushing is a tubular generally cylindrical bushing having peripheral relief means therein.
 17. The combination as set forth in claim 16 wherein adjustment means are provided to adjustably compress said bushing in said bore and thereby adjust the deflection rate of said bushing.
 18. The combination set forth in claim 14 including damping means arranged to resist lateral deflection and movement of said spindle shaft with a frictional force. 